In one embodiment, a system model models characteristics of a real-world system. The system model includes a plurality of sub-portions that each correspond to a component of the real-world system. A plurality of test vectors are applied to the system model and coverage achieved by the test vectors on the sub-portions of the system model is measured. In response to a failure of the real world system, a suspected failed component of the real-world system is matched to a particular sub-portion of the system model. A test vector to be applied to the real-world system to test the suspected failed component is selected in response to coverage achieved on the particular sub-portion of the system model.